1. Field of the Invention
The present invention generally relates to heat dissipation devices, and more particularly to a heat dissipation device having heat pipes for cooling an electronic device, such as an integrated circuit package.
2. Description of Related Art
Electronic components, such as central processing units (CPUs) comprise numerous circuits operating at high speed and generating a mass of heat that can be deleterious to their operation. Under most circumstances, it is necessary to cool the CPUs in order to maintain safe operating conditions and assure that the CPUs function properly and reliably. In the past, various approaches have been used to cool electronic components. Typically, a finned metal heat sink can be attached to an outer surface of the CPU to remove heat therefrom. The heat absorbed by the heat sink is then dissipated to ambient air. The related finned metal heat sink is made of highly heat-conductive metal, such as copper or aluminum, and generally comprises a solid metal base for contacting with the CPU to absorb the heat therefrom and a plurality of fins formed on the base for dissipating the heat. However, as the operating speed of electronic components has increased markedly in recent years, heat sinks that dissipate the heat only by metal conduction are insufficient and as a result, heat accumulated in a bottom of the metal heat sink cannot be transferred symmetrically to the whole heat dissipation device quickly enough.
Heat pipes, which operate by phase change of working liquid sealed in a hollow pipe, have been widely used due to their excellent heat transfer properties. Typically, a heat dissipation device has a base plate, a plurality of fins arranged vertically on a top face of the base plate, a plurality of heat pipes attached to a bottom face of the base plate and a heat-absorbing plate attached to a bottom face defined cooperatively by the heat pipes. The base plate defines a plurality of grooves receiving the heat pipes therein. In use, the heat-absorbing plate firstly absorbs heat from the electronic device and then transmits the heat to the heat pipes. The heat pipes transfer the heat to all parts of the base. The heat evenly distributed to the base is transmitted to the fins and is then dissipated to ambient air. However, the heat from the electronic device firstly transfers to the base by the heat pipes and then to the fins by the base. It fails to directly transfer the heat from the electronic device to the fins by the heat pipes. Thus, the heat dissipation efficiency is not high. In addition, the existence of the base plate increases cost and weight of the whole heat dissipation device.
Accordingly, what is needed is a heat dissipation device with heat pipes which has an enhanced heat dissipation performance and is inexpensive.